It’s well known that personalities can shift and change when we are ‘under the influence’ of chemicals, be it drugs or alcohol. As entomologists, we also consider this question for the insects and spiders that live among us: although we assume arthropods can similarly be affected by chemicals in their environment, it’s less clear how these chemicals may affect the personalities of these arthropods. We tested the effects of insecticide residues on the personalities of a jumping spider known to live in apple orchards. We found that individual-based personality shifts occurred when spiders were exposed to sub-lethal doses of an insecticide. This mean that even before we might see ‘population-level’ effects of insecticides on an important predator in agro-ecosystems, individual spiders themselves get, um, sort of messed up when under the influence.

How is this cute jumping sipder affected by insecticides? (photo by C. Ernst, reproduced here with permission)

Insecticides are often used in agriculture for various reasons, but can have negative effects on the ‘non-target’ fauna living in our agricultural fields. One of the most important challenges in evaluating their toxicity is that these chemicals can persist at low concentration in the environment. These concentrations are unlikely to kill exposed organisms but may substantially alter behaviours. Most of our evidence of the toxicity of insecticides on behaviours comes from studies on pollinators and research has shown decreases in spatial memory and learning capacities.

There remain gaps in our knowledge about how other types of organisms respond to these compounds. Studies on insecticide toxicity may be also limited because they tend to ignore how insecticides shape variation in behaviour. This is important because individuals differ in their behavioural tendencies and may not have the same weight in ecological processes: some individuals are more active, show more aggressiveness or consume more food. Personality traits can also be inter-related and form “behavioural syndromes”: clusters of behavioural traits that are correlated and evolve as a package. If personality traits are interconnected, any insecticide modifying one trait is likely to alter the whole syndrome. We’ve shown previously that behavioural syndromes differed between populations exposed and unexposed to insecticides in the Bronze Jumping Spider, a species common in apple orchards and known to prey on several economically important pests. But those populations could be different for a variety of reasons: for example, perhaps the insecticides affect spider behaviours because there is simply less food available in insecticide-exposed areas for example.

We wanted to test if insecticides could be directly responsible for the shifts in personality and behavioural syndromes we noticed. In other words, when a spider is “under the influence” of insecticides, is it still behaving according to its personality type?

The similarities between insecticides and drugs is fascinating: Both types of compounds target the nervous system, both can affect behaviours and both can kill above a certain lethal dose. In fact caffeine and nicotine evolved as natural plant defenses against insect herbivory and the latter was one of the first insecticides ever used. As crazy as it sounds, the effect of psychoactive drugs has been investigated in spiders in the past! The legend goes that, back in 1948, zoologist H. M. Peters was annoyed by his garden spiders spinning webs at “such ungodly hours” (2 am-5am). He wanted to found a compound that would shift the spinning behaviour to more a “decent” schedule, and he asked pharmacologist Peter N. Witt for help. Witt tried different psychoactive compounds on the spiders, including caffeine, LSD and marijuana but couldn’t produce the desired effect. What he found was in fact much more interesting: each compounds produced a distinct type of “drug web”, altering its shape, size or regularity ! (from Foelix’s “Biology of Spiders”) More recent research has shown that some commonly used insecticides affect web building in the same way drugs do.

We focused on how activity and prey capture capacities were affected by exposure to a widely used insecticide (phosmet) in the Bronze Jumping Spider. We tested activity and prey capture before and after exposure the insecticide and compared the amount of behavioural variation with that of a control group. Doing research in ecology sometimes requires using original equipment. In our case we found that the best way to expose our spiders to the insecticide was to use a hotdog warmer! We applied the insecticide solution on test tubes and used the rotation of the hotdog machine to get a homogeneous surface coated with dry insecticide residues. This allowed us to have a more precise control of the dose that each spider received while simulating field exposure conditions.

We did not found any effect of the insecticide on average behaviour between treatments but the ranking of individuals was strongly affected after insecticide exposure. In general spiders exposed to the insecticide were more variable in their behavioural tendencies. This suggests that the effects of insecticides on personality differences may manifest before any effects on the population as a whole are detected, in which case scientists may be frequently underestimating the toxicity of insecticides. Another puzzling result was that males and females did not respond in the same way to insecticide exposure. Males were most affected in the way they explored their environment but their capacity to capture prey remained intact. Females instead showed a decrease in the strength of the activity-prey capture syndrome.

Spiders play an important role in agricultural fields as they help regulate pest outbreaks. By altering personality differences and their syndromes, insecticides may limit spiders’ capacity to provide this important ecosystem service in subtle ways. As usual, this research leads to more questions than answers. At the organism’s level, it is important to understand how long these personality shifts last for. Do these shifts vary depending on how frequently spiders get exposed to insecticide or to what types of insecticides they are exposed to? How do they ultimately affect a spider’s capacity to escape predators, capture prey or reproduce depending on the individual’s personality? At the ecosystem level, prey get exposed to insecticides too, what happens to the predator-prey dynamics when the personality of both prey and predator is affected? How does that translate into biocontrol services? These are all important questions that I hope to contribute to in the future. Stay tuned!

So many clichés – the Arctic is a vast, stark landscape. In summer, a land of endless days, swarms of mosquitoes and rivers teeming with Arctic char; snowy owls flying low over the tundra; Muskox roaming the lands.

The clichés are true. I’ve been north many times, and each time the effect is stronger. Each time the landscape leaves a deeper impression. Over a couple of blog posts, I want to share reflections about the Arctic from my recent field trip to Cambridge Bay (Nunavut), and try to explain why I love it so much, and why Arctic research is my passion. I’ll also share a few of my favourite photographs from the trip.

Arctic Arthropods

I often write that “Arctic biodiversity is dominated by arthropods” and I stand firmly behind that statement. Despite the latitude of Cambridge Bay (at 69 degrees North), the tundra is alive with butterflies, bees, low-flying dipterans, and spiders. On a warm day, you can sit in the tundra and watch the careful movements of spiders as they navigate their three-dimensional world, seeking prey, or simply sunning themselves. Over the past few years our research team has documented over 300 species of spiders living across the Arctic and sub-Arctic, and although diversity drops at high latitudes, there are still over 20 species known from the low Arctic Islands, dropping to fewer than a dozen as you approach 80 degrees North.

Arctic wolf spider (Lycosidae), genus Alopecosa

Under rocks in flowing water you can find black fly larvae, swaying in the current. Sometimes you find the shield-shaped pupal cases, and if lucky, you can see the emerging adults. These emerging adults are sometimes adorned with red mites. There are arthropods living within the protection of Arctic willow; careful examination of Salix reveals red ‘berries’ which are actually galls. Opening these reveals a hidden life. A secret, protected room containing the larvae of a Hymenoptera.

An Arctic Lepidoptera (genus Boloria)

Research

A few years ago, the Federal Government announced a new Canadian High Arctic Research Station(CHARS), and it is to be built in Cambridge Bay over the next several years. This station will support and facilitate research in the North, in many different ways, from studies about effects of climate change on permafrost, to research on marine mammals. I am going to do my own research in Cambridge Bay, but with the aim of integrating research about arthropod biodiversity with other Arctic studies. I also hope to help in the development of a long-term monitoring plan, using arthropods as one of the focal taxon. Arthropods can tell us a lot about the world, and how it is changing, and long-term data are needed to ensure we have a clear sense of when ‘change’ is change that we need to pay particularly close attention to.

A malaise trap on the tundra – designed to collect flying insects

I was in Cambridge Bay to start to develop these kinds of projects, and to get to know the town, community and the land. I also wanted to collect insects and spiders in the Arctic in the late-season. I’ve worked in the Arctic a lot over the last several years, and although we have done full-season (i.e., June-August) collecting on the mainland, our laboratory does not yet have a clear idea about seasonal occurrence of different species occurring on the Arctic islands. Therefore, I was doing some collecting so that data could be gathered about arthropods on Victoria island and the end of the summer. For all these reasons, Cambridge Bay was my ‘research home’ for a week or so.

History and People.

Arctic regions of Canada have a rich history – and a history that is both tragic and awe-inspiring. Residential schools, relocation programs and stories of substance abuse, are all part of the darker side of this history. For hundreds of years, Europeans saw the Arctic as a wild land that required navigating, and a land that contained a bounty of riches, from whales to minerals. A bounty that was available for the taking. The stories are remarkable, and evidence of them remain in places like Cambridge Bay, including the influence of the Catholic church and the wreck of Amundsen’s ship, the Maud. The search for Franklin’s lost ships continues – while I was in Cambridge Bay, a ship departed, in search of the Erebus and the Terror.

The remnants of a Catholic church, built in Cambridge Bay in the early 1950s

The Maud, in its resting place. The townsite of Cambridge Bay is visible in the background

There has been a rebirth, however – Nunavut is a place of Inuit pride, and includes a wonderful balance between old traditions and new. The Inuit are marvellous – a people exhibiting patience, perseverance, kindness, good humour, and ingenuity. I heard stories of how runners on sleds could be made of frozen bodies of Arctic char, and the cross-braces from bones of wildlife, and frozen mosses would adorn the tops. If times were really tough, parts of the sled were edible. Today, wood and rope is the preferred construction material!

Sled on the tundra: waiting for winter.

Inuit culture is alive and well. I was lucky to spend time on the land with some of the locals, and I learned of edible plants, leaves that can be burned to ward of mosquitoes, and about the lice on arctic hare pelts. The Inuit are also fabulously artistic, well known for their carvings from bones and fur.

Very amazing stories sometimes come my way, and this one must be shared. Don Hardy (an artist, creator, and curious man!) approached me with a story and photographs of a 9 foot spider sculpture that he made. Don found me because of the spider bite story that came out a few weeks ago, and he and I immediately developed a rapport despite the fact that we live in different countries, and have different training (me, trained as a scientist; Don, trained as an artist). What do we share? A love of spiders: a love of their elaborate and unique anatomy, the way they move, and the way they have such an important place in our society – whether it be via adoration, fascination or terror.

So, let’s get right to the good stuff. Here’s what Don created.

The giant spider sculpture!

I am simply amazed and astounded by this beautiful creation!

I asked Don to provide me a few detail about the story behind his piece of art. Here are some exerts from his story, and Don has kindly given me permission to post this story, and his photographs.

I wanted to build a model of a spider for many years. The existing models and toys that I have seen were not real enough for me to appreciate so I decided to build my own version of a spider model. I studied many varieties of spiders and decided to use a combination of huntsman and wolf spider for my project. The initial inspiration was a huntsman spider due to an interesting experience I had at a pawn shop a couple of years ago. I was in the market for an electric piano and found one at a local pawnshop here in the Atlanta area. It was a Kawai model 330 missing the legs so I got a deal on it for 200 dollars! I brought it home and noticed that it had outputs for external speakers so I didn’t need to use the internal speakers at all. I could hook it up to my larger amp and get a bigger sound. I decided to take the internal speakers out and use them for another project later on. As I was taking one of the speakers out a large Huntsman spider came out of the hole! You can imagine how alarmed I was! I admit I jumped a little bit but soon relaxed after I noticed it was dead and dried up. I put it up and started to take out the second speaker. Another large Huntsman fell out of the second speakers hole! An unlikely duet! I put it up and continued to set up the piano for my other amp. The piano worked just fine. It gave me two giant huntsman spiders to contemplate!

Don then proceeded to study, measure and use these spiders as a model for his spider sculpture. Here’s what happened next, in Don’s words:

I used approx. a 40:1 ratio which would make my sculpture about 9 feet across with its legs fully extended. I made probably 20 trips to the local home improvement store and spent about 2 months working in the basement measuring, sawing, gluing, carving and bolting together the various boards, etc. that would replicate a spiders legs, pedipalps, fangs, sternum, cephalothorax and abdomen. I made templates for the eyes, fangs and abdomen. This helped with symmetry, size relationships and outlines for cutting. I also added heavy duty springs for leg tension so it could be self supporting.

I decided to go with a wolf spiders face which looked more interesting and fearsome to me. The wolfspiders eyes were much bigger and menacing than the huntsmans. And the anatomy was similar enough to switch over to a wolfspiders face without much difficulty. Once the basic structure was completed I started studying many images of huntsman and wolf spiders to paint a pattern on top. I probably used about 20 cans of spray paint before I was satisfied with the pattern. I used some artistic license but still stayed true to basic patterns. These spiders are masters of camouflage and the coloration and patterns blend in perfectly with grasses and terrain.

Halloween was fast approaching and I was able to display it in my neighbors yard. Amazingly some of the smaller children were crying and running from it thinking it was real! At first I built it as a static sculpture without any plans for further development. As I started studying what I created I realized that there was plenty of room for adding wires, motors and cables to make the fangs move, the pedipalps swing up and down and the abdomen to swing back and forth. Back to the workshop to add additional lifeforce! After drilling and a few more trips to the home improvement store I had a spider that had fangs that moved, pedipalps that swung in and out and an abdomen that shook back and forth!

Don and his spider friend.

Now it must surely be finished?

It stayed this way for about a year and then I realized I could make the two front legs raise upand down if I installed an actuator and cables on the sternum. I even went a step further and added servos and switches to the actuator and everything else so I could operate all the moving parts with a wireless transmitter! I purchased a Futaba four channel transmitter and four servos. I attached the servos to the sternum carefully lining up the wires and rods. After much tweaking I got it working quite well. The dream had of building a giant mechanical spider was finally coming true!

Um, yes, this giant spider sculpture moves. IT MOVES! Here’s a youtube video to show the sculpture in its full glory:

In summary, I sincerely thank Don for doing this incredible project, and also being keen to share it with the world. His work is a wonderful union of science and art.

This week I am thrilled to report that two of my MSc students have successfully completed their degrees! Both the projects are part of the collaborative Northern Biodiversity Program – a project aimed to quantify and understand ecological change with Arthropods from Canada’s north.

A BIG congratulations to Sarah Loboda and Katie Sim – they are both tremendously talented students, excellent Arachnologists, and wonderful people to know. Last night we had our annual Lab BBQ – and at that event, I was pleased to give Sarah and Katie a small token of appreciation. Here’s a photo showing them both with their wolf spider photographs (photos by the incredible Thomas Shahan):

Sarah Loboda’s thesis is titled Multi-scale patterns of ground-dwelling spider (Araneae) diversity in northern Canada. Her research focused on broad diversity patterns of ground-dwelling spiders collected from our 12 study sites, spread across Canada’s north. Our project spanned 30 degrees of latitude and 80 degrees of longitude –> yes that is a lot of land area! Sarah identified over 300 spider species from 14 families, and over 23,000 individuals. Publications are forthcoming so I won’t give details here, except to say that we can learn a lot about diversity patterns over broad spatial scales using a study taxon such as spiders.

Here’s where the Northern Biodiversity Program took our field teams.

Katie’s work (co-supervised by Prof. Terry Wheeler) had a different slant, but was still on Arctic spiders. Her thesis is titled: Genetic analysis of Pardosa wolf spiders (Araneae: Lycosidae) across the northern Nearctic. The first part of Katie’s thesis was about understanding the phylogeographic history of the Arctic spider Pardosa glacialis, with particular attention to post-glacial dispersal patterns, as inferred by population genetics. The second part of her thesis was focused on whether or not there is enough evidence to suggest two northern Pardosa species should remain as separate species, or be merged into one – based on both molecular and morphological characters. Let’s just say that Katie had to be a ‘field genius‘, ‘lab genius‘ and ‘spider genitalia genius‘. Here’s an example of what she looked at, a lot:

The epigynum of a wolf spider species, (part of) the topic of Katie’s research.

In sum, I am thrilled to see Sarah and Katie finish up their work, although their success also comes with a touch of sadness, as I will miss their daily presence in the laboratory. Stay tuned… we shall soon report all the details from their research.

It is well known that spiders are effective at dispersal and colonization, in part because of their ability to ‘balloon‘ – small spiders (i.e., immature specimens, or adults of species that are small) will release a strand of silk and let the wind pick them up and carry them far distances. This passive ability to disperse has served spiders well, and enabled them to be among the first animals to colonize new habitats. For example, after the eruption of Mount St Helens, the depopulated Pumice Plain was re-colonized over time, and biologists kept an eye on what was dropping from the skies. Not surprising (to me!) was that spiders represented a lot of this ‘aerial plankton‘ – Crawford et al. (1995) reported that spiders represented “23% of windblown arthropod fallout and contributed 105 individuals per square meter“.

A spider about to launch! Photo by Bryan Reynolds, reproduced here with permission.

Many, many people have recognized this amazing ability of spiders to get to places effectively and quickly. During his voyages on the HMS Beagle, Darwin observed and commented on this. He noticed spiders landing on the ship when they were far offshore. Here’s a lovely quote:

These, glittering in the sunshine, might be compared to diverging rays of light; they were not, however, straight, but in undulations like films of silk blown by the wind.

-Charles Darwin, Voyage of the Beagle, 1832

A wonderful paper titled “Distribution of Insects, Spiders, and Mites in the Air” (Glick 1939) also discusses aerial plankton. In this work, Glick reports on how a plane was used to collect arthropods in the skies – this was done by modifying the plane so it had a collection net attached to it. Spiders were among the most commonly collected taxa, and were found up to 15,000 ft in altitude. Glick followed this up with work published in 1957, and spiders were again reported as common aerial plankton.

Convinced? Spiders really are everywhere and can get anywhere – from dominating the tundra, to floating far above as tiny eight-legged aeronauts.

This takes me (finally) to the point of this post, and some reflection about a paper by Hodkinson et al. (2001), titled “What a wonderful web they weave: spiders, nutrient capture and early ecosystem development in the high Arctic – some counter-intuitive ideas on community assembly”. In this work, the authors provide some data about aerial plankton in a series of sites representing different stages of succession in Midtre Lovénbreen – a ‘small valley’ glacier in Spitsbergen (a Norwegian high Arctic Island). This forum paper was meant to present an idea about ecosystem development in the Arctic, with a focus on spiders and other aerial plankton and their relationship to nutrients.

Spiders are among the first to arrive due to their amazing abilities at dispersal and colonization.

Many spiders will just die, and their sad, little bodies will decompose and leave behind nutrients.

Many of the spider species that arrive will build webs, and the silk contains many nutrients. Regardless of whether the silk successfully captures prey, the silk will eventually be a hot-spot of nutrients.

A lot of other aerial plankton will hit these webs – this will include other arthropods (Hodkinson et al. rightfully point out the importance of Chironomids, or midges, as key prey for spiders in the north) and these prey may or may not be eaten by spiders. The aerial plankton also includes other ‘debris’ that would be floating around (fungal spores, dirt, etc). The webs capture all these goodies, and act as a concentrated area for a growing soup of nutrients.

The spider webs will collect moisture. In Arctic systems, dry polar-deserts, and many other newly created habitats, the accumulation of moisture is rather essential for continued ecosystem development.

Taken together, Hodkinson et al. (2001) argue that spiders and their webs represent little pockets of concentrated nutrients in landscapes that are void of much other life. These hotspots could be catalysts for ecosystem development in systems that are starting from scratch. I really like this idea – not only does is stir up the imagination (little spiders gently falling from the sky, landing on habitat never before touched by animals, and providing the start of an ecosystem…), it really makes some biological sense. Ecosystem development requires nutrients and substrates – of course, these would both be available without spiders, but our eight-legged friends are helping move things a long a little more quickly.

The paper by Hodkinson et al. has been cited less than I would have expected. Although they don’t provide any experimental data, their ideas are interesting and relevant and should be studied in detail. Recently, a few papers have come out that are taking the ideas to the next level. Konig et al. (2011) studied arthropods of glacier foregrounds in the Alps. They found that although Collembola and other ‘decomposers’ are quite important in early successional stages, overall, generalist predators (including spiders) were dominant and using stable isotope analyses, they showed that these generalist predators often ate each other – an interaction known as intraguild predation.

I often discuss Hodkinson et al.’s (2001) paper in lectures, and invariably I get the question “If spiders are first to arrive, what do they eat?“. I typically answer that spiders eat other spiders, and it’s reassuring to see literature that supports this claim. In turn, intraguild predation itself contributes further to the accumulation of nutrients (more sad, little spider bodies littering the landscape…).

Placing this work in a more general framework, these ideas are pointing to the increased importance of predators in overall nutrient dynamics in ecosystems. I was thrilled to see a paper by Schmitz et al. (2010) that argues “predators can create heterogeneous or homogeneous nutrient distributions across natural landscapes“. Bingo. This is exactly what Hodkinson et al. were arguing – predators, such as spiders, can arrive quickly to an area, and in the context of newly formed ecosystems, may provide a hotspot for nutrients in an otherwise desolate landscape.

Although the Hodkinson et al. paper is over a decade old, it’s still relevant, and quite important. I suspect that if more newly created habitats are studied in detail, spiders will indeed prove to be catalysts for ecosystem development.